This invention relates broadly to high frequency switching circuits and more particularly to drive circuitry for achieving switching of power transistors.
High frequency switching regulators are being increasingly used as a result of their high efficiency, reduced physical size and weight and low audible noise levels. To achieve the high frequency operation, fast transistors with fast rise and fall times are required together with proper drive circuitry. Industry is now providing new, improved switching transistors and Schottky diodes to enable high frequency operation.
The next step is to provide driving circuitry which can take advantage of the high frequency capabilities of these improved switching transistors. Such a circuit must first provide fast turn-on and turn-off of the power transistors. The speed of turn-on and turn-off is directly related to the efficiency of the circuit since power is dissipated during switching times. The shorter the switching time, the less power is wasted. Furthermore, it is desirable to avoid configurations which require heat sinks and to minimize components.